title: Compound-specific stable carbon isotope analysis of galaxolide enantiomers in sediment using gas chromatography/isotope ratio monitoring mass spectrometry.
abstract: BACKGROUND
  Both chiral analysis and compound-specific stable carbon isotope analysis have limitations when applied to environmental research. However, the combination of these two techniques might overcome their respective limitation and give more insight into the enantioselective fate and source apportionment of chiral organic contaminants.
  
  
  METHODS
  After Soxhlet extraction and clean-up, sediment extracts were further pre-concentrated using normal-phase preparative high-performance liquid chromatography to isolate sufficient quantities of highly purified galaxolide (1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta(g)-2-benzopyran; HHCB). The enantiomeric fractions and stable carbon isotopes of the HHCB were determined using gas chromatography/mass spectrometry (GC/MS) and GC/isotope ratio mass spectrometry (IRMS).
  
  
  RESULTS
  The method was validated by analysis of the enantiomeric fractions and the stable carbon isotope ratios of the HHCB standard at each step of the pre-concentration procedure, and no significant enantiomeric and isotopic fractionation was found. The sediment sample was further used to test the developed method, and it was shown that the HHCB enantiomers in the sediment sample exhibited significantly different δ(13) C values (-33.03 to -24.57‰) and a slight enantiomeric fractionation (0.507 and 0.490) from a HHCB standard reference compound (-26.50 to -26.21‰ for δ(13) C values, and 0.519 and 0.497 for enantiomeric fractions).
  
  
  CONCLUSIONS
  This work offers a novel approach to elucidating the sources and the abiotic or biological transformation processes of HHCB in the environment and will offer a perspective for assessing the environment fate of any chiral organic compound.
authors.affiliation: State Key Laboratory of Organic Geochemistry, Guangdong Key Laboratory of Environment Protection and Resource Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China.
authors.forename: Jingzhi
authors.initials: J
authors.lastname: Wang
authors.forename: Shutao
authors.initials: S
authors.lastname: Gao
authors.forename: Xiangying
authors.initials: X
authors.lastname: Zeng
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Yu
authors.forename: Ping'an
authors.initials: P
authors.lastname: Peng
authors.forename: Guoying
authors.initials: G
authors.lastname: Sheng
authors.forename: Jiamo
authors.initials: J
authors.lastname: Fu
mesh_terms: D001578:Benzopyrans / Q000737:chemistry*; D002247:Carbon Isotopes / Q000032:analysis; D002849:Chromatography, Gas / Q000379:methods; D004785:Environmental Pollutants / Q000737:chemistry*; D019015:Geologic Sediments / Q000737:chemistry*; D013058:Mass Spectrometry / Q000379:methods; D013237:Stereoisomerism
chemical_list: D001578:Benzopyrans; D002247:Carbon Isotopes; D004785:Environmental Pollutants; C033119:galaxolide